Natural light is essential for any room in the house. So, the lack of it may become a real problem. Brightness and airiness of the room always make it more comfortable and inviting. Of course it is not always possible to make a new window in the wall, but you might consider using a new window treatment. But at first, do not forget about a simply cleaning of the window. Sometimes the result may exceed the expectations. If nothing helps, try adding mirrors and bright colors to the room.